Counter flow air conditioner



July 16, 1935. L. u. LARKIN 2,008,255

COUNTER FLOW AIR CONDITIONER Filed Nov. 1e, 193s 2 sheets-sheet 1 ,/f C.MTP DVA H Mnjnwqldww@ A@ @N S Q. mm Q@ s @Mfma'gsfmwm drm c LA July 16,1935. L, u. L ARKIN COUNTER FLOW AIR CONDITIONER Filed Nov. 16, 1935 2Sheets-Sheet 2 w mi LESTER LAreK/N 5f www? Patented July 16, 1935 PATENToFFlcE COUNTER FLOW CONDITIONER Lester U. Larkin, Atlanta, Ga., assignorto Larkin Refrigerating Corporation, Atlanta, Ga., a corporation ofGeorgia Application November 16, 1933, Serial No. 698,291

2 Claims'.

This invention relates generally to Ventilating air cooling systems;and, more particularly tov cooling systems adapted for use in the formof small compact highly efcient units for cooling air in refrigerateddisplay counters or cases, market refrigerators, cold storage rooms, andthe rooms of residences, oice buildings, etc.

In residence and office cooling it is ordinarily desirable to decreasethe humidity of the air as it passes through the conditioner; since, adecrease in humidity results in a greater rate of evaporation ofperspiration in the persons subjected to the conditioned air. In thiscase, the cooling unit is comparatively small, and the temperaturedifference is likewise comparatively small, since comfortable livingconditions never require the air to be lowered anywhere near thefreezing point. In other Words, a small cooling unit circulating hothumid air will decrease the humidity thereof.

On the other hand, a comparatively large unit used for refrigerationpurposes in a cooler or cold storage room may cause an increase inrelative humidity, since the conditioned air is usually brought down totemperatures around the freez-A ing point. This refrigeration,obviously, causes shrinkage of the air originally in the cooler, andwith a consequent suction of outside air, and its moisture content, intothe cooler to compensate for this shrinkage. This results in an increasein relative humidity of the air in the cooler. This means that decreaseor increase in humidity of a compartment or room will depend upon thesize of the cooling unit as compared with the 35 size of saidcompartment or room, and with the drop in temperature which the unit isdesigned to effect.

The main object of the invention, therefore, is

to provide an air conditioning unit which is 40 highly efficient inoperation, and in which the relative humidity of the air conditioned maybe considerably increased by the cooling operation of the unit, or maybe decreased where this is found necessary or desirable.

Other objects of the invention will become apparent as the detaileddescription thereof proceeds.

In the drawings:

Figure 1 is a top plan view of an air conditioning unit embodying thepresent invention, part of the casing being removed to illustratedetails of construction;

Figure 2 is a vertical section taken on the line 2 2 of Figure 1; A

Figure 3 is a top plan View, similar to Figure 1, showing a modifiedform of the invention; and

Figure 4 is a vertical section taken on the line 4 4 of Figure 3.

In Figures 1 and 2 of the drawings, the unit is shown as comprising abase plate I, extended 5 rearwardly to form a support 2 for a motor 3having its rotor shaft 4 extending in opposite directions from the motorcasing. On each side of the motor there are arranged the blower casings5 and 6 constructed to communicate at their upper ends with the conduitI forming part of an air cooling casing designated generally by thenumeral 8.

The casing 8 comprises the base plate I, side walls 9 and I0, a top IIand partitions I2 and l5 I3 extending across the casing parallel to thebase plate I and dividing the casing into three conduits 1, I4 and I5.The conduits 'I, I4 and I5 are substantially equal in size, and aredimensioned so that each conduit can accommodate at least two grids of acooling coil formed of piping having an outlet I 6 at the Warm air inletof the conduit l. The top II is connected to the partition I3, at theexit end of the casing 8, by a semi-cylindrical casing Il; and the baseplate I is likewise connected by a semi-cylindrical plate I8 to themotor end of the partition I2. By this arrangement, the conduits l, I4and I5 form a continuous counterlow duct for conducting air from the airinlet I9 of the unit to the air outlet 20 thereof.

As will be apparent from the drawings, the piping forming the upper gridin the conduit 'I extends from the refrigerant outlet or suctionconnection I6 to the exit end of the casing 8. At this exit end, a bend2I connects the upper grid 22 to the lower grid-23 in the conduit l. Thelower grid 23 at the inlet end of the casing 8 is connected by a bend24, which extends through the partition I2, to the upper grid 25 in thecondnit I4. At the exit end of the casing 8, which is also the inlet endof the conduit I4, the upper grid 25 is connected by a bend 25 to thelower grid 2'I in the aforesaid conduit I4.

At the inlet end of the casing 8, the grid 21 is connected by a bend 28,passing through the partition I 3, with the grid 29 in the upper part ofthe conduit I5. The grid 29, at the exit end of the casing 8 and of theconduit I5, is connected by a bend 30 to the lowermost grid 3I, which,at the inlet end of the casing 8, is connected to the inlet end 32 ofthe entire coil system contained within the several conduits 1, I4 andI5.

It will be noted from the foregoing disclosure thatv the Warm air forcedinto the conduit 'I by the blowers contacts with the warmest part of thecooling coils. 'Ihis construction and mode of operation enables therefrigerant to absorb the greatest number of heat units possible for ltto contain at temperatures prevailing at the exit or suction endthereof. In this respect, the present cooling unit operates directlyopposite to the Acooling devices of the prior art.V In other words,

the warm air contacts the warmest part of the coil; and the cold orconditioned air emerges from the coldest end of the unit.

This arrangement and mode of operation have the effect -of reducing orpractically eliminating condensation. It is obvious that the nearer thetemperature of the coil to that of the air impinging thereon, the lesswill be the condensation. This effect continues throughout the entirelength of the conduits from inlet to exit. In other words, the decreasein temperature of the air being conducted through the air ducts of theunit is effected gradually and not in sharp steps as would be the caseif the warm air were forced initially against the coldest part of thecoil system to emerge at the warm end thereof. v

The grids of each compartment are traversed by aseries of fins 33,preferably of aluminum, and extending perpendicularly to theconvolutions of the grids in each compartment. These ns are preferablyconstructed and arranged on the grids substantially as disclosed in theUnited States patent to Larkin, No, 1,776,235, September 16, 1930; andeach extends substantially the entire length of the conduit ln which itis arranged.

As disclosed in the aforesaid Larkin patent, the coils provided withthese vertical flns are highly eicient and reduce the temperatures ofair passing therethrough with great rapidity. Moreover, the temperaturedifferential between the coils and the air conditioned thereby is sosmallthat to bring the air down to any desired temperature, it is onlynecessary to maintain the refrigerant inlet end of the coil at about onede.

gree below that of the air as it emerges from the exit end of the unit.

It must be distinctly understood that this invention is not to beconsidered as in anyway limited to the number of air conduits arrangedvin the casing, or to the number of grids of cooling coils which may bearranged in-each conduit. It must also be understoodthat the inventionis not to be considered as vlimited to-the use of any particular numberof cooling grids in each conduit. It is desirable, of course, that thecoldest end of the coils shall be at the exit end of the casing. Thisresult could obviously be obtained by using three grids zigzagged in theconduit I5. However, the nal result is not substantially affected byusing thetwo grids as shown in conduit I5, and which, therefore, requirethe cold inlet end of the coil system to be positioned at the warm airend of the unit. In the ideal system, however, the cold inlet of thecooling coils should be located at the cooled air exit.

In the modification shown in Figures 3 and 4, the blower mechanism andcasing are substantially the same as the blower mechanism, and casingshown in Figures land 2; and the corresponding parts thereof aredesignated by the ranged with a motor at the bottom of the counter so asto expel cold air out o-f the top of the unit toward the center of therefrigerator in which case it may be convenient to use a duct extendingfrom the outlet of the unit along the top of the counter case. The unitmay also be disposed with the motor and fans below the tori of thecounter to expel the cold air toward the center ofthe case and along thebottom thereof. In other words, the operation of the invention disclosedherein is not in any way dependent upon its being arranged in anyparticular position in any refrigerator or compartment.

While not shown nor described in this application, it is to beunderstood that the unit will be provided with the usual adjustablethermostatic controls to regulate the operation of the refrigerant coilsand the temperature of the air conditioned by the unit. ThesethermQstatic switches and valves controlled thereby are very well knownin this art; and form no essential part of the present invention.

It is thought that the invention and numerous` of its attendantadvantages will be understood from the foregoing description, and it isobvious that numerous changes may be made in the form, construction andarrangement of the several parts Without departing from the spirit orscope of my invention, or sacrificing any of its attendant advantages,the form herein described being a preferred embodiment for therpurposeof illustrating my invention.

What I claim is:

1. An air conditioner comprising: a casing having a series of superposedconduits extending lengthwise therethrough, means for connecting theadjacent ends of said conduits in series to provide a continuouscircuitous air duct through all of said conduits, meansfo'r forcing airthrough said duct, means extending transversely of each conduit forcooling the air during its passage mounted in saidcasing and having gridbranches extending substantially across each of said conduits, andcooling fins extending lengthwise of each conduit and Vin heatconducting contact n across said branches. y

LESTER U. LARKIN.

